Method and Device for Updating Area in Wireless Communication System

1. A method for processing an area update request of a user equipment (UE) in a network node, the method comprising: receiving an area update request message from the UE; determining whether to accept an area update request based on the area update request message when the network node is congested; accepting the area update request message when the area update request message includes indication information indicating that the UE moves to a new area that is not registered by the UE while a backoff timer is running at the UE; and rejecting the area update request message when the area update request message does not include the indication information.

2. The method according to claim 1 , further comprising transmitting an area update request accept message to the UE when the area update request message is accepted.

3. The method according to claim 2 , wherein, if the UE receives the area update request accept message while the back-off timer is running in the UE, the back-off timer is maintained until the back-off timer expires.

4. The method according to claim 1 , wherein, when the area update request is accepted, if the UE receives a paging message while a back-off timer is running, the UE stops the back-off timer and performs a response to the paging message.

5. The method according to claim 1 , wherein the new area is a new tracking area (TA), a new routing area (RA), or a new public land mobile network (PLMN).

6. The method according to claim 5 , wherein the new TA or the new RA is a TA or an RA not included in a TA list or an RA list registered by the UE.

7. The method according to claim 1 , wherein the area update request message is one of a tracking area update (TAU) message, a routing area update (RAU) message, a combined TAU message, and a combined RAU message.

8. The method according to claim 1 , wherein the area update request message is transmitted even when a back-off timer is running in the UE.

9. The method according to claim 8 , wherein the area update request message is transmitted when the UE enters the new area even when the back-off timer is running.

10. The method according to claim 8 , wherein a value for the back-off timer is included in a non-access stratum (NAS) reject message from a network before the UE enters the new area.

11. The method according to claim 8 , wherein the back-off timer is a mobility management (MM) back-off timer.

12. A network node for processing an area update request of a user equipment (UE), the network node comprising: a transceiver; and a processor that: controls the transceiver to receive an area update request message from the UE, determines whether to accept the area update request based on the area update request message when the network node is congested, accepts the area update request message when the area update request message includes indication information indicating that the UE moves to a new area that is not registered by the UE while a backoff timer is running at the UE, and rejects the area update request message when the area update request message does not include the indication information.